[33602] in Kerberos
Re: leaking rcache opens in gss_accept_sec_context
daemon@ATHENA.MIT.EDU (Benjamin Coddington)
Wed Jul 20 08:48:21 2011
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From: Benjamin Coddington <bcodding@uvm.edu>
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Date: Wed, 20 Jul 2011 08:48:15 -0400
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To: Greg Hudson <ghudson@mit.edu>
Cc: "kerberos@mit.edu" <kerberos@mit.edu>
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On Jul 20, 2011, at 1:07 AM, Greg Hudson wrote:
On Tue, 2011-07-19 at 16:21 -0400, Benjamin Coddington wrote:
>> gss_acquire_cred
>> gss_accept_sec_context
>> gss_export_lucid_sec_context
>> gss_delete_sec_context
>
>> I found that before we got to gss_delete_sec_context(), we had already
>> tried to clean up the context in gss_krb5_export_lucid_sec_context()
>> -> krb5_gss_delete_sec_context(), which fails with G_VALIDATE_FAILED.
>> It also sets the context to GSS_C_NO_CONTEXT, so once we get to
>> gss_delete_sec_context(), context validation fails there too.
>
> Aha. Yes, that's the bug you found a reference to. (And thank you for
> explaining why that bug wasn't resulting in gssd crashes for everyone in
> previous releases. I had forgotten about the pointer validation code.)
> I've attached the patch which is due for krb5 1.9.2.
>
> gss_delete_sec_context should be unnecessary when
> gss_export_lucid_sec_context succeeds. Of course, it's harmless given
> the way GSS handles contexts (nulling out the pointer when they are
> released).
>
> <patch.txt>
Thank you, Greg. I can confirm that this fixes the problem we were seeing.
It also fixes a leak when running without '-n', which was less obvious because we didn't open a new handle to the rcache each time.
Ben
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